In the packaging field it is known to partly or wholly fill spaces in corrugated paperboard with sulphur foam (Jacquelin U.S. Pat. No. 3,787,276), with urethane foam (Rodgers, Jr. U.S. Pat. No. 2,973,295), or with injection molded thermoplastic material such as polyethylene, polypropylene or styrene (Santangelo U.S. Pat. No. 3,364,638). In cases where water seepage resistance is necessary corrugated paperboard panels may be rendered moisture impervious by filling the spaces with colloidal clay such as bentonite (Clem U.S. Pat. No. 3,186,896).
It has also been proposed to use corrugated paperboard panels filled as with asbestos fibers and expanded perlite particles as building panels in much the same manner as plywood sheets are currently used (Wandel U.S. Pat. No. 3,449,157). Another known form of laminated building sheet or panel comprises a corrugated metal spacing member with holes through the sidewalls of the corrugations sandwiched between metal facing sheets with the spaces between the facing sheets and corrugated sheet being filled with cellular asbestos having the cells thereof disposed transversely to the corrugations and keyed in the holes in the sidewalls of the corrugations (Coffman U.S. Pat. No. 2,234,517).